1. Field of the Invention
The present invention relates to a solid-state imaging apparatus, an A/D converter, and a control method thereof.
2. Description of the Related Art
In order to speed up the operation of a CMOS image sensor which incorporates A/D converters, a technique for parallel executing of read-out processing of analog signals from pixels, and A/D conversion of the readout analog signals has been proposed. For example, Japanese Patent Laid-Open No. 2008-067358 describes that two capacitors are provided to a ramp A/D converter, a pixel signal of a given row is held in one capacitor, the held pixel signal is A/D-converted, and a pixel signal of the next row is written in the other capacitor. In each capacitor, one electrode is fixed to a reference voltage, and the other electrode is connected to a pixel. Then, the electrode connected to the pixel is re-connected to a comparator, thus A/D-converting the pixel signal held in the capacitor.